Is there a way to not limit vertex painting to visible geometry?
This may not be a direct answer, but you could try the following:


Enter Edit Mode, turn off the limit (marked in red), and use the brush to select vertices you want to paint:

Then enter Vertex paint Mode, and turn on the face selection mask:

It doesn't matter where you click with your brush, because the paint is limited to the selected faces



Results are (at the front)


and (at the back)